Bottom hole choke for plunger lift devices



Oct. 31, 1933. H. w.FLE'rcHER BOTTOH HOLE CHOKE FOR PLUNGER LIFT DEVICES Filed Jan. 9, 1932 VIIIIJVIAJIllllllllllllllflllllll Illlllll rl FIG.1

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I'NVENTOR HARoLn w. FLETCHER ATToRNE-Y Patented Oct. 31, 1933 UNITED STATES BOTTOM `HOLE CHOKE FOR PLUNGER LIFT DEVICES Harold W. Fletcher, Houston, TeX., assigner to Hughes Tool Company, Houston, Tex., a co1'- poration of Texas Application January 9,

4 Claims.

My invention relates to a flow choke to be employed at the lower end of the eduction tube in a plunger lift apparatus.

It is an object of the invention to check the flow of fluid from the well into the eduction tube so as to allow smoother and more effective operation or" the apparatus.

In raising the plunger with its load of liquid to the surface without a choking means at the lower end of the tube the gas and liquid from the well tend to rise quickly behind the plunger and to blow up behind the same and prevent the proper dropping of the plunger after its working stroke. I contemplate avoiding this difficulty by slowing down the entrance of fluid to the tube. l

In the drawing herewith, Fig. 1 is a central longitudinal section through a plunger lift equipment at the upper end of the installation.

Fig. 2 is a similar sectional View of the lower end of the installation shown in position in the well.

I have shown the well as equipped for at least a portion of the distance into the well with a casing 1 projecting above the ground and having at its upper end a casing head 2. Said casing head has a lateral branch 3 through which iluid may enter or pass from the well. This line may be controlled by a hand-operated valve 4. The upper end of the casing head is threaded at 5 for engagement with a bonnet 6, which is reduced in diameter at its upper end and threaded internally at 7 for engagement with the eduction tube extension 8.

Within the casing head is an inwardly projecting ilange 9 upon which is supported the head 10 secured to the upper end of the eduction tube 11. Said head has a radial ange resting upon the shoulder 9 and making a close fit with the interior of the casing head. A gasket 12 may be placed upon theA shoulder 9 to assure a iluid seal between the tube and the lower portion of the casing head.

The eduction tube 11 projects from the surface downwardly so as to submerge the lower end within the liquid in the well. The lower end may be provided with a strainer plug 13 thereon. Said plug is connected by means of a coupling 14 to the lower end of the tube, and tting within the coupling and secured between the ends of the plug and the tube is a ring or collar 15 upon which is supported the bottom choke member 16. Said choke member is adapted to t closely within the tube at its lower end and is tapered upwardly so as to be engaged by a locking collar 1932. Serial No. K 585,695

17 and thus held frictionally within the tube. The choke member is provided at its lower end with an inlet orice'18, which is of the proper size to restrict the flow of fluid from the wellY to the interior of the eduction tube.

Above the orifice 18 the passage 19 is flared upwardly to discharge within the passage 29 through the clamping collar.

The clamping collar is cylindrical on its outer surface and has its interior beveled or liared downwardly to engage over the upper end of the' choke member and wedge the said member rigidly in position. Th'eopeningthrough the upper end of the clamping collar through which th fluid passes also furnishes engagement for a spear or grab by means of which the clamping member may be removedfirom the tube.

The head l0 at the upper end of the eduction tube is formed on its inner surface to t closely against the lower end oi the eduction tube eXten sion 8. 'Ihis connection makes a close joint between the head and the tube extension, allowing the rotation on said extension when the tube or the bonnet 6 with the tube therein is secured in position. Within'the casing head the tube extension is provided with longitudinal openings 21 through which the uid from the tube may be discharged. The upper end of the extension is closed by a cap 22, which may have therein a sleeve 23 of rubber or other compressible material, furnishing a buier or shock absorbing member when the plunger rises beyond its usual height. At one side of the casing head 2 and connected with the chamber 24 within the casing head is the discharge outlet 25 through which the fluid may pass to storage.

The plunger shown herein is of the usual form now generally employed in this apparatus and comprises abody 26 cylindrical on its outer surface and having its inner wall converging downwardly to provide a stream line passage for fluid through the same. At the lower end of the body is connected the ring 27 having a valve seat 28 thereon and connected with a supporting block 29 by means of legs 30. The block 29 has a cir cular recess 31 at its upper end to support the valve 32 in position spaced below the seat when the valve is in open position. The valve stem 33 projects through a guide opening in the block 29 and the luid within the tube has access to the 105 lower end of said valve stem through openings 34 in the lower end of the block 29.

In the operation of this device the gas produced from the well will accumulate in the space 35 between the wall of the well and the eduction 110 Cil tube and will force the liquid upwardly in the eduction tube above the seat provided at the upper end of the clamping sleeve 17. When suicient head of liquid is accumulated above the plunger back pressure will be exerted upon the gas entering the lower end of the tube sufcient to cause the gas below to raise the valve 32 to its seat after which the plunger with its load of liquid will be raised to the surface, ,discharging the liquid through the openings 21 to the dis-Y charge pipe 25.

When the plunger has passed the openings 21` it will move into the closed upper end of the tube extension and the valve will be forced open by the back pressure of fluid trapped in the upper end of the tube. The plunger will thus be allowed to drop back in the tube tothe lower end thereof ready to repeat the operation.

It has been found, however, that where the inflow of gas and liquid at the lower end of the tube -is allowed to operate unchecked that it will interfere with the dropping of the plunger and in some cases may even force the valve to closed position. It is to overcome this situation that the choke member 16 is provided. The gas and liquid can enter only at a gradual and slow rate of speed sufficient to raise the liquid above the seat in the clamping collar l'lbut not in such amount as to interfere with the smooth operation of the plunger on its downward stroke. It will be obvious that the size of the orifice 18 in the choke member may be varied to suit the circumstances in the particular well being operated, and if conditions change it is possible to lower va spear into the well and remove the choke member and substitute therefor another one of the choke devices properly regulated as desired.

What I claim as new is:

1. In a plunger lift device, a single string of eduction tube therein, means adjacent the upper end thereof to allow discharge of fluid therefrom, a choke member in said tube adjacent the lower end to retard the passage of both gas and liquid into said tube, a clamping collar securing said choke member rigidly in position, and a plunger movable by fluid pressure above said choke member.

f V2. In a plunger lift device, an upper well casing, a single string of eduction tube therein, means adjacent the upper end thereof to allow discharge of fluid therefrom, a choke member in said tube adjacent the lower end to retard the passage of fluid into said tube, said choke member comprising a plug for said tube having a restricted orifice therein, and a clamping collar wedging about said plug to hold the said plug in position.

3. In a plunger lift device including a single string of eduction tube and vaplunger working freely therein from the lower end to the upper end thereof, the combination of a choke device Limiting the rate of ow of fluid to said tube and a seat for said plunger above said choke.

4. vIn a. plunger lift device for wells including an eduction tube and a plunger movable therein from the lower end to the upper end thereof, the improvement comprising raising said plunger in said tube by the force of gas accumulating in the well and checking the now of fluid into the lower end of salid eduction tube, to prevent a strong now of gas upwardly in said tube after said plunger has reached its upper limit of movement and thus allowing said plunger to drop back.

HAROLD W. FLETCHER. 

